Authorizing the Use of a Motor Vehicle

ABSTRACT

A method for authorizing the use of a motor vehicle by a portable identification transmitter is provided. According to the method, a first vehicle antenna emits a first signal, which is received by an identification-transmitter antenna. The identification transmitter determines at least one of the spatial components of the first electromagnetic field of the received first signal. A second vehicle antenna emits a second signal, which is received by the identification-transmitter antenna. The identification transmitter determines at least one of the spatial components of the second electromagnetic field of the received second signal. A computer determines the angle between the determined spatial component of the first electromagnetic field and the determined spatial component of the second electromagnetic field. The identification transmitter transmits an authorization signal for authorizing use of the motor vehicle to the motor vehicle only if the angle exceeds a predetermined threshold value.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No. PCT/EP2016/068884, filed Aug. 8, 2016, which claims priority under 35 U.S.C. § 119 from German Patent Application No. 10 2015 016 552.6, filed Dec. 18, 2015, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for authorizing the use of a motor vehicle that has at least a first antenna and a second antenna, wherein the first antenna and the second antenna are at a physical interval from one another. The motor vehicle is in particular a two- or four-wheeled motor vehicle.

In the case of such known methods, it is desirable for them to be further improved against manipulations.

An object of the invention is to provide a method for authorizing the use of a motor vehicle with improved protection against manipulations.

This object is achieved by a method for authorizing the use of a motor vehicle having the features of the independent method claim. Advantageous configurations of the method according to the invention are the subject matter of the dependent method claims.

The method according to the invention proceeds from a method for authorizing the use of a motor vehicle, in particular a two- or four-wheeled motor vehicle, that has at least a first antenna and a second antenna, wherein the first antenna and the second antenna are at a physical interval from one another, by a portable identification transmitter that has an identification transmitter antenna.

This known method is developed according to the invention by the following steps.

In a first step, the first vehicle antenna emits a first signal that is received via the identification transmitter antenna.

In a second step, the identification transmitter ascertains at least one of the spatial components of the first electromagnetic field of the received first signal, preferably using an angle-resolving magnetic field sensor.

In a third step, the second vehicle antenna emits a second signal that is received via the identification transmitter antenna.

In a fourth step, the identification transmitter ascertains at least one of the spatial components of the second electromagnetic field of the received second signal, preferably using the angle-resolving magnetic field sensor.

In a fifth step, a first computer, preferably a computer in the identification transmitter, ascertains the angle at least between the ascertained spatial component of the first electromagnetic field of the received first signal and the ascertained spatial component of the second electromagnetic field of the received second signal.

In a sixth step, the identification transmitter sends an authorization signal for authorizing the use of the motor vehicle to the motor vehicle only if the ascertained angle exceeds a predetermined threshold value.

In summary, the method according to the invention allows at least two physically separate or spaced transmitters to be used to determine the position of the receiver or of the identification transmitter in angle-resolved fashion. If the signals of the spaced transmitters are forwarded by a repeater with the intention of manipulation, the delay time is extended and the angle information is lost. The angle-resolving method according to the invention detects such manipulation of the radio link by virtue of the parallelism of the signals being detected by the identification transmitter and the latter preventing the emission of an authorization signal.

In one configuration of the method according to the invention, there is provision for the interval of time between the emission of the first signal by the first vehicle antenna and the emission of the second signal by the second vehicle antenna to be chosen to be such a short time—but different than zero—that the identification transmitter carried by the driver is largely not moved when the driver approaches the vehicle, and therefore the ascertainment of the angle at least between the ascertained spatial component of the first electromagnetic field of the received first signal and the ascertained spatial component of the second electromagnetic field of the received second signal is largely not distorted, or does not become unusable, as a result of the movement of the driver, or as a result of the associated movement of the identification transmitter.

The above measures allow particularly reliable ascertainment of the angle and hence particularly reliable determination of whether the predetermined threshold value is exceeded to be achieved.

In accordance with a further embodiment of the method according to the invention, the motor vehicle has a further, third antenna that is at a physical interval from both the first antenna and the second antenna and in that analogously or in the same way the angle at least between the ascertained spatial component of the first electromagnetic field of the received first signal and the ascertained spatial component of the third electromagnetic field of a third signal emitted by the third antenna and received by the identification transmitter is determined.

These measures allow the reliability during the ascertainment of the angle, and hence the determination of whether the predetermined threshold value is exceeded, to be increased further.

In an advantageous configuration of the method according to the invention, there is provision for the spatial components of the first electromagnetic field of the received first signal that are ascertained by the identification transmitter to be the x, y and z components of the electromagnetic field of a first Cartesian coordinate system.

In accordance with an advantageous development of the method according to the invention, there is provision for the spatial components of the second electromagnetic field of the received second signal that are ascertained by the identification transmitter to be the x, y and z components of the electromagnetic field, largely the components with reference to the first Cartesian coordinate system. This is the case largely because the Cartesian coordinate system or reference system underlying the ascertainment of the components changes only slightly in spatial terms in the event of slight movements of the identification transmitter in very short periods between the repeated ascertainment of the angles.

In one configuration of the method according to the invention, the spatial components of the third electromagnetic field of the received third signal that are ascertained by the identification transmitter are the x, y and z components of the electromagnetic field, largely those of the first Cartesian coordinate system.

The above measures allow a particularly reliable determination of the angle between the ascertained spatial components of the first electromagnetic field of the received first signal and the ascertained spatial components of the second electromagnetic field of the received second signal and/or between the ascertained spatial components of the third electromagnetic field of the received third signal to be achieved.

In an advantageous development of the method according to the invention, there is provision for at least a first vector from the x, y and z components of the first electromagnetic field of the received first signal that are ascertained by the identification transmitter and a second vector from the x, y and z components of the second electromagnetic field of the received second signal that are ascertained by the identification transmitter to be formed computationally and, from these two vectors, the scalar product thereof to be formed computationally.

In accordance with a particularly advantageous development of the method according to the invention, the scalar product is used to computationally determine the angle between the two vectors.

Computing the angle between the two vectors using the scalar product requires only a small computational outlay or a low processor power.

In accordance with a particularly preferred embodiment of the method according to the invention, there is provision for the ascertained angle to exceed a predetermined threshold value of largely zero degrees, in particular a threshold value greater than 1 to 10 degrees, preferably 1 to 5 degrees.

In an advantageous development of the method according to the invention, the threshold value that is greater than zero degrees is increased as the distance of the identification transmitter from the vehicle decreases. Preferably, the distance is determined by a delay-time measurement between the signals that are interchanged between vehicle and identification transmitter.

In accordance with a preferred embodiment of the method according to the invention, there is provision for the first, second and third antennas each to send on an identical or different frequency in a frequency range from 20 kHz to 140 kHz, preferably on approximately 125 kHz, and preferably with staggered timing.

The above measures allow the reliability of the method according to the invention for authorizing the use of a motor vehicle to be improved additionally.

Besides the advantageous method according to the invention for authorizing the use of a motor vehicle, the invention allows the provision of a vehicle entry system for authorizing the use of a motor vehicle, the vehicle entry system being involved in the performance of a method according to the invention or performing a method according to the invention.

In an advantageous development of the vehicle entry system according to the invention, there is provision for the identification transmitter to be a radio key or a smartphone, preferably with an identification transmitter software application, such as what is known as an app.

In accordance with an advantageous configuration of the vehicle entry system according to the invention, the identification transmitter is a smartphone provided with a computer chip, a radio vehicle key provided with a computer chip or a chip card with a computer chip.

In one embodiment of the vehicle entry system according to the invention, the identification transmitter has a sensor for determining or ascertaining an electromagnetic field and/or the components of the electromagnetic field that has been generated by one or more vehicle antennas in the region of the identification transmitter.

The above features of the vehicle entry system according to the invention allow the driver to be provided with particularly convenient use of the method according to the invention for authorizing the use of a motor vehicle.

The invention moreover proposes an engine immobilizer for authorizing the use of a motor vehicle that is advantageously involved in the performance of a method according to the invention or performs a method according to the invention.

Further, a motor vehicle is proposed that has provision for at least one step of a method according to the invention as claimed in one of the preceding claims to be performed in the motor vehicle.

Finally, the invention proposes a non-transitory computer-readable medium for controlling at least one processor that prompts the execution of at least one step of a method according to the invention.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. A method for authorizing use of a motor vehicle that has at least a first antenna and a second antenna, wherein the first antenna and the second antenna are at a physical interval from one another, by a portable identification transmitter that has an identification transmitter antenna, the method comprising: emitting, by the first vehicle antenna, a first signal that is received by the identification transmitter antenna; determining, by the portable identification transmitter, at least one of spatial components of a first electromagnetic field of the first signal; emitting, by the second vehicle antenna, a second signal that is received by the identification transmitter antenna; determining, by the portable identification transmitter, at least one of spatial components of a second electromagnetic field of the second signal, using an angle-resolving magnetic field sensor; determining, by a computer in the identification transmitter, an angle between the determined spatial component of the first electromagnetic field of the first signal and the determined spatial component of the second electromagnetic field of the second signal; and sending, by the identification transmitter, an authorization signal for authorizing use of the motor vehicle to the motor vehicle only if the determined angle exceeds a predetermined threshold value.
 2. The method for authorizing the use of the motor vehicle as claimed in claim 1, wherein an interval of time greater than zero between emission of the first signal by the first vehicle antenna and emission of the second signal by the second vehicle antenna is chosen such that the portable identification transmitter carried by a driver is largely not moved when the driver approaches the motor vehicle, and therefore determination of the angle between the determined spatial component of the first electromagnetic field of the first signal and the determined spatial component of the second electromagnetic field of the second signal is largely not distorted, or does not become unusable, as a result of movement of the driver, or as a result of associated movement of the portable identification transmitter.
 3. The method for authorizing the use of the motor vehicle as claimed in claim 1, wherein the motor vehicle has a third antenna that is disposed at a physical interval from both the first antenna and the second antenna, and the angle between the determined spatial component of the first electromagnetic field of the first signal and a determined spatial component of a third electromagnetic field of a third signal emitted by the third antenna and received by the portable identification transmitter is determined.
 4. The method for authorizing the use of the motor vehicle as claimed in claim 1, wherein the spatial components of the first electromagnetic field of the first signal that are determined by the portable identification transmitter are x, y and z components of the electromagnetic field of a first Cartesian coordinate system.
 5. The method for authorizing the use of the motor vehicle as claimed in claim 4, wherein the spatial components of the second electromagnetic field of the second signal that are determined by the portable identification transmitter are the x, y and z components of the electromagnetic field of the first Cartesian coordinate system, largely because the Cartesian coordinate system or reference system underlying determination of the components changes only slightly in spatial terms in an event of slight movements of the portable identification transmitter in very short periods between repeated determination of the angles.
 6. The method for authorizing the use of the motor vehicle as claimed in claim 4, wherein the spatial components of the third electromagnetic field of the third signal that are determined by the portable identification transmitter are the x, y and z components of the electromagnetic field of the first Cartesian coordinate system.
 7. The method for authorizing the use of the motor vehicle as claimed in claim 4, wherein at least a first vector from the x, y and z components of the first electromagnetic field of the first signal that are determined by the portable identification transmitter and a second vector from the x, y and z components of the second electromagnetic field of the second signal that are determined by the identification transmitter are formed computationally and, from these two vectors, a scalar product thereof is formed computationally.
 8. The method for authorizing the use of the motor vehicle as claimed in claim 7, wherein the scalar product is used to computationally determine the angle between the two vectors.
 9. The method for authorizing the use of the motor vehicle as claimed in claim 8, wherein the determined angle exceeds a predetermined threshold value of 1 to 5 degrees.
 10. The method for authorizing the use of the motor vehicle as claimed in claim 9, wherein the threshold value is increased as the distance of the portable identification transmitter from the vehicle decreases, wherein the distance is determined by a delay-time measurement between signals that are interchanged between the vehicle and the portable identification transmitter.
 11. The method for authorizing the use of the motor vehicle as claimed in claim 3, wherein the first, second and third antennas each send on an identical or different frequency in a frequency range from 20 kHz to 140 kHz with staggered timing.
 12. A vehicle entry system for authorizing use of a motor vehicle, comprising: at least a first antenna and a second antenna, wherein the first antenna and the second antenna are at a physical interval from one another; and a portable identification transmitter that has an identification transmitter antenna; wherein the first vehicle antenna is configured to emit a first signal that is received by the identification transmitter antenna, and the portable identification transmitter is configured to determine at least one of spatial components of a first electromagnetic field of the first signal; wherein the second vehicle antenna is configured to emit a second signal that is received by the identification transmitter antenna, and the portable identification transmitter is configured to determine at least one of spatial components of a second electromagnetic field of the second signal, using an angle-resolving magnetic field sensor; wherein a computer in the portable identification transmitter is configured to determine an angle between the spatial component of the first electromagnetic field of the first signal and the spatial component of the second electromagnetic field of the second signal; and wherein the portable identification transmitter is configured to send an authorization signal for authorizing use of the motor vehicle to the motor vehicle only if the determined angle exceeds a predetermined threshold value.
 13. The vehicle entry system for authorizing the use of the motor vehicle as claimed in claim 12, wherein the portable identification transmitter is a radio key or a smartphone with an identification transmitter software application.
 14. The vehicle entry system for authorizing the use of the motor vehicle as claimed in claim 12, wherein the portable identification transmitter is a smartphone provided with a computer chip, a radio vehicle key provided with a computer chip or a chip card with a computer chip.
 15. The vehicle entry system for authorizing the use of the motor vehicle as claimed in claim 12, wherein the portable identification transmitter has a sensor for determining at least one of an electromagnetic field and components of the electromagnetic field that have been generated by one or more vehicle antennas in a region of the portable identification transmitter.
 16. The vehicle entry system for authorizing the use of the motor vehicle as claimed in claim 13, wherein the portable identification transmitter has a sensor for determining at least one of an electromagnetic field and components of the electromagnetic field that have been generated by one or more vehicle antennas in a region of the portable identification transmitter.
 17. The vehicle entry system for authorizing the use of the motor vehicle as claimed in claim 14, wherein the portable identification transmitter has a sensor for determining at least one of an electromagnetic field and components of the electromagnetic field that have been generated by one or more vehicle antennas in a region of the portable identification transmitter.
 18. A non-transitory computer-readable medium comprising computer instructions executable by a processor to cause the processor to perform a method for authorizing use of a motor vehicle that has at least a first antenna and a second antenna, wherein the first antenna and the second antenna are at a physical interval from one another, by a portable identification transmitter that has an identification transmitter antenna, the method comprising: emitting, by the first vehicle antenna, a first signal that is received by the identification transmitter antenna; determining, by the portable identification transmitter, at least one of spatial components of a first electromagnetic field of the first signal; emitting, by the second vehicle antenna, a second signal that is received by the identification transmitter antenna; determining, by the portable identification transmitter, at least one of spatial components of a second electromagnetic field of the second signal, using an angle-resolving magnetic field sensor; determining, by a computer in the identification transmitter, an angle between the determined spatial component of the first electromagnetic field of the first signal and the determined spatial component of the second electromagnetic field of the second signal; and sending, by the portable identification transmitter, an authorization signal for authorizing use of the motor vehicle to the motor vehicle only if the determined angle exceeds a predetermined threshold value. 